LG eXpo GW820

troubles with device sound

Daes anyone of LG eXpo owners have had a problem with a noisy background during phone calls?... It happens when the other caller is calling from an open space ( mall, street, etc ) that they can barely hear me and has precluded to use any headset bluetooth. I've tried different 4 bluetooth and it's the same with all: I have to disconnect my phone from it when I receive a call from someone in the open. To top it all, I couldn't find the way to manage mic functions in this device. Can anyone help me?